A multicentre cohort involving over 13,000 HIV-positive patients has been established in the UK, and is described in the March 2004 edition of HIV Medicine. The establishment of the cohort is intended to provide long-term follow-up on a large and diverse population of HIV-positive individuals.
Patients receiving care at seven major HIV treatment centres since 1996 have been enrolled in the cohort, called the UK Collaborative HIV Cohort (UK CHIC) Study. The aims of the UK CHIC Study are to describe the frequency of AIDS-defining illness and deaths, the uptake and response to HAART and the factors associated with virological and immunological response to HIV treatment. Information will also be collected on hepatitis B and hepatitis C coinfection, adherence to anti-HIV treatment regimens and treatment interruptions.
The UK CHIC Study was initiated in 2001 and involves six HIV treatment centres in London (Chelsea and Westminster Hospital, King’s College Hospital, Mortimer Market Centre, St Mary’s Hospital, St Thomas’s Hospital, and the Royal Free Hospital), as well as the Brighton and Sussex University Hospital. It is hoped to include other HIV treatment centres in the future.
All patients aged 16 years or over who were receiving HIV care at any time since 1996 (the year HAART was introduced to the UK) have been enrolled in the cohort.
Electronic information including patients' demographic details, AIDS diagnoses, CD4 and CD8 cell counts, viral loads, and HIV treatment history has been provided by each treatment centre. Data is updated for each individual every six to nine months. A random selection of 1% of records is then manually audited to ensure concordance between electronic records and written clinical records. As it is possible for HIV-positive individuals in the UK to request care from any HIV treatment centre, the UK CHIC Study investigators have taken steps to ensure that records are not duplicated for individuals receiving care at more than one hospital.
A total of 13,833 individuals from six of the seven participating centres are enrolled in the cohort (data from St Thomas’s were unavailable). Of these, 82.2% are men, the median age is 34 years, 62.8% have sex between men as their HIV exposure category, and 23.8% sex between men and women. Over half (56%) are described as white, 26% have developed AIDS, and 8% have died.
Since 1996 approximately 1,000 individuals a year have been added to the cohort. These patients have reflected the shifting epidemiology of the HIV in the UK, with the proportion of female patients increasing from 12.5% in 1996 to 17.5% in 2003. At the same time the proportion of gay men in the cohort fell from 72.2% to 66.4%, and the total proportion of heterosexuals increased from 16% to 24.1%. Changes can also be observed in the ethnicity of patients added to the cohort. In 1996, 61.7% of patients in UK CHIC were white, by 2003 this had fallen to 58.1%, with the percentage of Black Africans increasing from 9% in 1996 to 16.9% in 2003. Comparison with UK government data shows that the UK CHIC is representative of the broader HIV epidemic in the UK.
The UK CHIC Study investigators intend to link information from their cohort to the recently established National HIV Resistance Database.
It is planned to include patient representation on the cohort steering committee, which also involves clinicians, epidemiologists, statisticians, as well as representatives from the Medical Research Council and ethics committees.
Further information on this website
Record 7,000 new HIV diagnoses in UK in 2003 - news story
HIV prevalence increases by 20% in UK in one year - news story
UK Collaborative HIV Cohort Steering Committee. The creation of a large UK-based multicentre cohort of HIV-infected individuals: the UK Collaborative HIV Cohort (UK CHIC) Study. HIV Medicine 5: 115 - 124, 2004.